posted on 2018-11-08, 17:11authored byColin R. Fishenden
Low-speed tests have been carried out on a branched annular
diffuser system having a geometry similar to that employed in some gas
turbine engine combustion systems. The system comprised a straight
walled pre-diffuser followed by a sudden area expansion in which the
flow was divided between two concentric annuli separated by a bluff
body simulating a combustion chamber. The overall geometric area ratio
was maintained at 2.0 and all tests were carried out with fully developed
flow at inlet. The design flow split between the outer and inner annuli
was 2.15:1. The system was tested with five different pre-diffuser
geometries to show the effect of increasing the area ratio, increasing
the included angle and canting the pre-diffuser. For each pre-diffuser
geometry the influence of varying the flow split and the axial distance
between pre-diffuser outlet and combustion chamber head (dump gap) were
investigated. In addition to determining the overall performance
characteristics, the pressure losses for the inner and outer flow fields
were calculated and the losses further sub-divided in order to identify
regions of high loss. [Continues.]
Funding
Great Britain, Ministry of Defence, National Gas Turbine Establishment.
History
School
Aeronautical, Automotive, Chemical and Materials Engineering
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Publication date
1974
Notes
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of the degree of Doctor of Philosophy at Loughborough University.